Field of the Disclosure
The present disclosure is related to the medical field and, more particularly, to an expanding needle and expanding needle device for use with fluid delivery and transfer systems.
Description of Related Art
Needles and spikes are used in medical procedures and techniques, such as for drug preparation, drug delivery, and collection of fluid samples. A needle generally includes a tubular body having a tip or point sharpened on a distal end thereof. Needles for medical use are often formed from medical grade metal materials, such as stainless steel, by a tube drawing process. The needle may be connected to a retaining structure, such as a needle hub, which is connected to a fluid source or fluid conduit.
Fluid flow rate through a needle is limited by a combination of the pressure exerted on the fluid, such as by a plunger or stopper of a syringe, and the inner diameter of the needle. Accordingly, wider needles provide a faster flow rate. However, wider needles may cause increased pain when inserted through a patient's skin and may cause increased bruising at the injection site.
In addition, in fluid transfer applications, wider needles core septa and seals, preventing the septa or seal from properly resealing once the needle is removed. More specifically, during a fluid transfer activity, a technician, nurse, pharmacist, or other trained professional pushes a needle attached to the syringe through a piercable septa covering an opening of a medical vial to establish fluid communication between the vial and syringe barrel. Once fluid communication between the barrel and vial interior is established, fluid can be drawn into the syringe, to prepare a syringe for injection, or expelled into the vial, such as during drug reconstitution. The fluid flow rate through the needle is dependent on the cross sectional area of the needle and the pressure developed within the syringe barrel. However, the cross sectional area of the syringe is necessarily limited since a needle having a large cross sectional area would core the piercable septa when inserted therethrough. A septa that has been cored may not seal correctly once the needle is removed therefrom leading to fluid leakage or contamination. Accordingly, a needle intended to pierce a resilient septa generally is not larger than 16 gauge.
More recently, automated drug compounding systems have been developed. Such automated systems include electro-mechanical components for performing one or more of the following functions: inserting a needle into a fluid container, such as a vial or bag; for drawing fluid from the container; and/or for expelling fluid into the container from a fluid source, such as a syringe barrel. Operational speed for such automated systems is limited by the fluid flow rate through the needle. Accordingly, operational speed for such systems is related to a cross sectional area of the needle.
Systems and devices have been developed for increasing fluid flow rate between containers through a needle. For example, transfer devices for safe fluid transfer of chemotherapy agents are known. Such systems or devices increase the flow of makeup air into the vial to assist in drawing fluid from the vial. However, such systems are most concerned with operator safety, namely preventing an operator or patient from being exposed to air or fluid from within the interior of the vial. Accordingly, such systems often do not substantially increase flow rate through the needle. In addition, such chemotherapy agent transfer systems are complex requiring means, such as an inflatable balloon or collapsible chamber, for providing airflow to or from the vial or container. Finally, such systems are most concerned with providing makeup air for the vial and, accordingly, may not increase flow rate or operating speed when fluid is expelled from a fluid source, such as a syringe, into the vial.
Expandable tubular bodies, which may expand to increase fluid flow rate are known in other fields. For example, stents are expandable tubular bodies formed from a metal or polymer mesh material that expand when exposed to heat. A stent is inserted through a catheter into the vasculature of a patient while in a contracted state. Once the stent reaches a desired location, the stent is expanded to provide structural support for a vein and to ensure proper fluid flow therethrough. U.S. Pat. No. 4,969,890 to Sugita et al. discloses an exemplary stent formed from a shape memory alloy tubular piece that includes a rolled Ni—Ti sheet that radially expands when heat is applied thereto.
Guide wire assemblies may be used for providing vascular access for insertion of a catheter and stent. For example, U.S. Pat. No. 8,663,168 to Chin et al. discloses a flexible needle formed from nitinol hypodermic tubing and designed so that the needle will bend as it is advanced through a patient's vasculature. Similarly, U.S. Pat. No. 7,803,142 to Longson et al. is directed to a needle that includes a sheath having defined slots therein. The needle may be formed from a shape memory alloy, such as nitinol, so that an interior structure can spread the sheath outward. The sheath expands to allow a guide wire assembly and catheter to pass through the expanded needle lumen. However, these expandable tubular bodies are not used for fluid delivery or fluid transfer applications. Particularly, the expandable portions of these tubular bodies include slots or openings and, as such, cannot be used for fluid transfer applications. In addition, the nitinol alloy material used for such flexible needle assemblies is chosen for its large strain capability, rather than for its shape memory properties.